3) Did Mann splice in real temps into the proxies ? (I would find this incredible)

4) If we have increasing real temperatures and decreasing proxies, and if we add the decreasing proxies (1960 or 1980 on) would the regression equation on temp on the proxies be statistically insignificant ?

5) If the regression equation is statically insignificant; a) we cannot infer prior temps, or b) the recently reported real temps may have been massaged ?

I do not know as much as some others but…
1) try harder. Check when each proxies was physically collected. I would expect that few researchers would want to collect proxies for decades where much more sophisticated ways of measuring things were around. The point of using a proxy is to understand the past.

2) The context of the hide the decline phrase/comment does not suggest this. It is supposed to be shorthand for some sophisticated statistical manipulation (not deleting real data). Most of the data he used for his analysis was not even collected by him or his colleges but something that was shared (original copy not in his control).

3) If I understand correctly that was part of the type of stat trick but I do not understand that area of statistics well enough. If you search through the scientific papers that Mann cited, there should be one or two explanations for pros to understand.

4) As far as anyone knows proxies in general are not declining but specific types may be. There are also so many different proxies to keep track of that it makes my head spin to think about it. Search Science-direct or some other database. Depending on which proxy data you look at, from which location, you will get different results (only a fraction of which will match your 1960-1980 decline claim).

5) a mismatch could mean a problem with anything. The most reasonable explanation would be that the techniques for inferring past temps you are using are not so great. to my knowledge, none of the individuals accused of dishonesty in climategate had much of any involvement with measuring the temperatures. The CRU does not control the thermometers around the world. They just contact researchers in other countries and ask for data. Whenever P. Jones gets lucky, the foreigners read their e-mails and respond if they feel like it.

Perhaps naive question: Today’s temperatures are recorded from stations all over the world, and any lack of coverage is considered a weakness. But aren’t proxies generally confined to limited geographical areas? A tree’s rings, assuming they tell us anything at all, could tell us only about the temperature in the one place where the tree grew. So why do people take these proxies so seriously?

Hi, Jonathan,
Proxy data is not really confined to limited geographical areas. Looking at tree rings over the whole earth can present a partial picture of past climate in all of these different locals. Tree ring data can only hint at the temperature during the time of the tree’s growth. Tree ring growth says more about the water supply to the tree, in other words the conditions under which the tree grew, or the climate. Other proxy data must be used to complete the picture. The reason tree ring data is taken so seriously is because the data is isolated or incapsulated and cannot be contaminated by outside variables. Once the ring has completed its formation or seasonal growth , “something” cannot enter the tree and alter that formation. That “something” might be able to alter a subsequent, new developing tree ring, but that alteration would clearly be seen when the tree’s rings were examined. This is why tree rings are an important part of understanding climate and climate changes.

Re Tree Ring “Proxies”
Tree growth rates are a compound of temperature and watersupply. Any home gardener could figure that out.

On what possible basis then could people with PhD’s and professorships propose tree rings as a temperature proxy without at the very least a concurrent record of water supply at the same location?

No wonder the Saudi’s think this is all so much doo doo, its not their vested interest in selling oil, its their long experience in lots of temperature with no water = no trees. To them it is a no brainer.

Even more interestingly, wouldn’t tree rings depend on CO2 concentration over long timescales? Plants grow faster as CO2 concentrations rise. So couldn’t tree rings be a proxy for CO2 rather than temperature?

In which case, it wouldn’t really be surprising if the tree ring “temperature” record correlated with CO2 – because it would really be a CO2 record!

The leaves of trees are used as a CO2 proxy. There are also more than half a dozen other proxies for CO2. Which variable correlates most strongly with growth rates depends on which species of tree you are looking at. Theoretically if you had a species for each variable, you would be able to get really good ideas of past atmospheres.
In general, how fast a plant grows depends of what variable is limiting (like a scarce nutrient).

Over long timescales I meant more than yearly. In other words, obviously the CO2 concentration varies across the year, but the tree ring thickness presumably would depend on average CO2 concentrations over periods of more than one year.

But the fact remains – if more CO2 means that tree rings get wider, then thicker tree rings could be the result of higher CO2 as well as higher temperature.

the thing that always got be about the “hockey stick” analysis was that planetary albedo was not modelled as a variable yet consideration of greenhouse effect first principles says it is and a significant one. Even if Stephen McIntyre & Ross McKindrick and others had not analysised the mathematical modelling Mann et al’s work would remain fundamentally and fatally flawed.

The only decent analysis I have come across which models albedo is by Ermakov, Okhlopkov and Stozhkov and which uses a fourier transform to model the constituent contributions to temperature variation over time.

and another thing…Ifyou compare the temperature record since about 1850 of the globe, the two hemishperes and the difference between the two an interesting pattern emerges. The SH ( where I live) is on avereage about 0.1C cooler than the NH but over the past decade that has opened up to about 0.3 degrees. This suggests to me that the two hemispheres act quite differently in their contribution to the global average. That the two are geographical opposites, that is NH is largely land with a polar sea surrounded by land mass and the SH the opposite seems to me that their albedo behaviour is likely quite different and that perhaps the NH tends to drive a warming and the SH a cooling phase. This is also consistent with the various dynamic interactions of the seas and atmoshere from N to S.

Has the following e-mail from the CRU/climategate regarding Yamal treerings been commented on CA? It clearly shows that Briffa have tried to alter the conclusion delt with in Hentemirov 2002 in accordance with the teams effort to show the last centuries “unprecedented warmth”

Dear Keith,
thank you very much for editing our paper.
It’s a pity you strike your name off the list of authors, you
make an important contribution to writing paper. Your corrections
and additions surely improve paper.

I would only notice the next sentence (page 8):

‘The low interannual variability and the minimum occurrence of
cold extremes during the 20th century, argue that the most recent
decades of this long summer record represent the most favourable
climate conditions for tree growth within the last four
millennia.’

I’m not sure that this statement follows unambiguous from results
presented in this paper. Because mean temperatures during last
decades, according presented reconstruction, are not exceptional.
Besides, e.g. period about 1700 BC, according this
reconstruction, represent probably the same conditions taking
into account low variability, low occurrence of extremes and high
mean temperature.
May be to soften this statement and replace ‘the most favourable’
with something like ‘highly favourably’ or ‘probably the most
favourable’?

Thank you once more for invaluable assistance.

Best regards,
Rashit M. Hantemirov

(I’m sorry for the late answer, I just come back from the trip to
the north.)

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